Hi Henry. I disagree. The final grades of a fines product is never the same as a coarse grade because the grain size of all the constituent minerals is so different. Also, the metallurgical route taken for the fines circuit employs flotation, which pulls some minerals that a DMS doesn't and vice versa. The flotation circuit has to be tweaked, so as to produce a saleable product, which meets the minimum Li20 content and the maximum content of deleterious elements. Having a fines product helps a spodumene producer, because you can actually vary the blends of fines/coarse to avoid penalties and to incorporate feedback from the downstream producer.
If I'm talking nonsense, I'd love to engage in meaningful dialogue with qualified persons.